C>(> 
WOODPECKERS IX BELATION TO TREES. 
To recapitulate, figures 9A to !>I) show wounds 1 year old 
healed in various ways. Least progress is shown in B and C, in both 
of which the wound has failed to close. A conical projection is 
formed on the inside of the hark, which makes a deep depression in 
following wood layers, as is illustrated by figure 10A. Figures A 
and 1) show wounds promptly closed by more vigorous growth. 
In figure A, as the peck extended only to the sapwood, the succeed- 
ing annual layer is smooth internally and because of small growth 
only slightly distorted externally under the hark hole. In figure D 
one ping of sapwood is entirely and another partly pierced. The 
new growth has been so thrifty that the original peck has been filled 
and a plug also pushed out into the bark opening. Methods of heal- 
ing as illustrated by figures 9A, 9D, and 10B produce a pit on the 
inner side of the bark which 
causes corresponding eleva- 
tions in succeeding layers of 
wood. As a rule, then, if the 
growth following sapsucker 
wounds is vigorous, succeed- 
ing layers of wood will be 
bent outward over the 
wound; if weak, the grain 
will bendinward. In either 
case radial sections (fig. 10) 
of the wood reveal the curl 
in the grain and tangential 
sections cutting through the 
curls show a condition re- 
sembling natural bird's-eye 
(PL IX, fig. 6). As it can 
usually be recognized from the arrangement of the bird's-eyes in 
rows (see PI. Xlf) corresponding to the well-known type of sap- 
sucker work in the bark, it may well receive the name of sapsucker 
bird's-eye. 
The question now arises, What is the effect of sapsucker work 
upon the commercial value of hard maple wood? The bird's-eye 
and curl, and even small stains if hard and sound, may he considered 
as ornamental and as enhancing the value of the wood. But exten- 
sive staining, a. common accompaniment of sapsucker work in hard 
maple, is detrimental. Furthermore, the original pecks, if on the 
surface, appear as cavities surrounded by bleached and stained wood 
'PI. IX, fig. 1), which must he planed oil' before the wood can he 
put to decorative use. The strength of the wood is not greatly 
affected except when pecks are numerous in a single annual layer, 
in which case this layer constitutes an easy splitting plane. 
Fig. 10. — Effects of sapsucker work on wood of sugar 
maple (Acer saccharum). (From Hopkins. ) 
